Questions such as how much fresh water we have left on Earth, where it is located, and how we can access it are all nearly impossible to answer. However, scientists working on understanding and revealing the planet's surface structure are helping to hone in on an answer. University of British Columbia researchers have created a world's-first with their new map that outlines how fluid flows through Earth's various porous surfaces. Information gleaned from the map can help us discover more about water supplies worldwide. According to Science Daily, the maps, published earlier this week in Geophysical Research Letters, could help with both water resource management and climate modeling, since a better understanding of how fluid permeates rock and sediments can reveal how and where rainwater travels as it flows into the water table. While most maps so far have dealt with permeability down to one or two meters of soil, and across smaller areas, this new map tracks permeability to depths of about 100 meters across the globe.

"This is the first global-scale picture of near-surface permeability, and is based on rock type data at greater depths than previous mapping," says Tom Gleeson, a postdoctoral researcher with the Department of Earth and Ocean Sciences.

Mapping groundwater supplies in such detail is important for managing use of water, especially in where and how much is extracted. Such water source mapping has helped recently in uncovering to what extent groundwater supplies in southern Asia are contaminated with arsenic. Researchers were able to create a 3D map to show that the deeper a well went for water, the more likely it was to be contaminated.

We still don't know exactly how much fresh water we have left, but we know it is shrinking and we are hitting (or have already hit) peak water, since we're draining aquifers, over-exploiting rivers, and dropping the groundwater table ever deeper.